Abstract
We introduced eight fish pathogen phages and three Escherichia coli phages (T4, T7 and λ) into the intestinal tract of goldfish Carassius auratus by anal intubation (108.3 PFU/fish). All phages appeared in the kidney at mean PFUs ranging from 102.7 to 104.3 PFU/g 3 h after intubation. Anal intubation of a representative Pseudomonas plecoglossicida phage (PPpW-4) into goldfish revealed that the introduced phages transfer to the blood and kidney within 10 min and are retained there for at least 12 h. An intubation dose of 107.3 PFU/fish or higher is required for constant presence of the phages in the circulatory system. Our results indicate that phages have the ability to pass through the intestinal wall and spread to the circulatory system, suggesting the potential application of phage therapy with oral administration.
